51 research outputs found

    Obituary: Arthur Cruickshank 1932 - 2011. A native Gondwanan, who studied the former continent's fossil tetrapods

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    Dr Arthur Richard Ivor Cruickshank died on 4th December 2011, aged 79, in the Borders General Hospital, Melrose, Scotland. Arthur Cruickshank was part of the post-war generation of palaeontologists who laid the foundations on which today’s researchers build. Appropriately for someone from an expatriate Scots family living in Kenya, much of his work was on the extinct reptiles of the great southern palaeocontinent of Gondwana

    New UV-Curable Anticorrosion Coatings from Vegetable Oils

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    Bio-based epoxy resins are attracting widespread interest in the field of polymer thermosets as environmentally friendly building block. In the present study, the feasibility of applying UV-curable epoxidized vegetable oils (EVOs) as anti-corrosion coating is investigated. Rheological characterization of EVOs is carried out, and their viscosity-shear relationship is evaluated. The cationic UV-curing of EVOs successfully gives rise to crosslinked materials with a wide range of thermo-mechanical properties, evaluated by differential scanning calorimetric analysis and dynamic thermal mechanical analysis. A high epoxy-group conversion, ranging from 93% to 99%, is always obtained. The thermal stability and surface properties of the bio-based coatings, such as, pencil hardness, adhesion, solvent resistance, and contact angle, are analyzed. Moreover, the corrosion protection effectiveness of the coatings is characterized by potentiodynamic polarization and electrochemical impedance spectroscopy measurements. In addition, field emission scanning electron microscopy is used to assess the samples morphology after corrosion tests

    The tail of the Jurassic fish Leedsichthys problematicus (Osteichthyes: Actinopterygii) collected by Alfred Nicholson Leeds - an example of the importance of historical records in palaeontology

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    The specimen of the tail of <i>Leedsichthys problematicus</i>, now in The Natural History Museum, London, was one of the most spectacular fossil vertebrates from the Oxford Clay Formation of Peterborough, but as an isolated find it shares no bones in common with the holotype of the genus and species. However, a letter from Alfred Nicholson Leeds and related documents cast valuable new light on the excavation of the tail, indicating that it was discovered with cranial bones, gill-rakers, and two pectoral fins, thereby including elements that can potentially be compared with those of the holotype. The documents also clearly indicate that The Natural History Museum's specimen is not part of the same individual as any other numbered specimen of <i>Leedsichthys</i> as had been speculated on other occasions. The maximum size of the animal represented by The Natural History Museum's specimen was possibly around 9 metres, considerably less than previous estimates of up to 27.6 metres for <i>Leedsichthys</i>. Historical documentary evidence should therefore be rigorously checked both when studying historical specimens in science, and in preparing text for museum display labels

    Rivestimenti epossidici fotopolimerizzati derivati da oli vegetali = UV-cured epoxy coatings from vegetable oils

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    This study presents the characterization of innovative epoxy coatings derived from vegetable oils. They are photopolymerized materials derived from epoxidized grape seed oils or epoxidized rose hip seed oils. A complete characterization of the coatings was performed, both to study chemico-physical properties such as contact angle and glass transition temperature, and to investigate their corrosion protection effectiveness. The coatings were deposited on mild steel substrates and then characterized by means of Electrochemical Impedance Spectroscopy (EIS) in order to analyse their barrier properties. A good protection effectiveness was found, specifically for the coatings characterized by a higher crosslinking density. Thus, results show the possibility to optimize the barrier properties of these bio-based materials by means of a proper choice of the precursor oils

    Literature review on the ‘Smart Factory’ concept using bibliometric tools

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    The objective of this paper is to depict a landscape of the scientific literature on the concept of the ‘Smart Factory’, which in recent years is gaining more and more attention from academics and practitioners because of significant innovations in the production systems within the manufacturing sector. To achieve this objective, a dynamic methodology called "Systematic Literature Network Analysis (SLNA)" has been applied. This methodology combines the Systematic Literature Review approach with the analysis of bibliographic networks. The adopted methodology allows complementing traditional content-based literature reviews by extracting quantitative information from bibliographic networks to detect emerging topics, and by revealing the dynamic evolution of the scientific production of a discipline. This dynamic analysis allowed highlighting research directions and critical areas for the development of the "Smart Factory". At the same time, it offers insights on the fields on which companies, associations, politicians and technology providers need to focus in order to allow a real transition towards the implementation of large-scale Smart Factory

    Haplotype Affinities Resolve a Major Component of Goat (Capra hircus) MtDNA D-Loop Diversity and Reveal Specific Features of the Sardinian Stock

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    Goat mtDNA haplogroup A is a poorly resolved lineage absorbing most of the overall diversity and is found in locations as distant as Eastern Asia and Southern Africa. Its phylogenetic dissection would cast light on an important portion of the spread of goat breeding. The aims of this work were 1) to provide an operational definition of meaningful mtDNA units within haplogroup A, 2) to investigate the mechanisms underlying the maintenance of diversity by considering the modes of selection operated by breeders and 3) to identify the peculiarities of Sardinian mtDNA types. We sequenced the mtDNA D-loop in a large sample of animals (1,591) which represents a non-trivial quota of the entire goat population of Sardinia. We found that Sardinia mirrors a large quota of mtDNA diversity of Western Eurasia in the number of variable sites, their mutational pattern and allele frequency. By using Bayesian analysis, a distance-based tree and a network analysis, we recognized demographically coherent groups of sequences identified by particular subsets of the variable positions. The results showed that this assignment system could be reproduced in other studies, capturing the greatest part of haplotype diversity

    Methylphosphonium methylcarbonate, ylide precursor for halyde- and base-free Wittig reactions

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    The phosphonium salt triphenylmethylphosphonium methylcarbonate [PΦ,Φ,Φ,1][OCOOCH3] was obtained by methylation of triphenylphosphine (Ph3P) with dimethylcarbonate, adopting a green and sustainable procedure1. The [PΦ,Φ,Φ,1][OCOOCH3] phosphonium salt was observed to possess significant P-CH3 proton acidity, and deuterium exchange experiments showed the formation of the analogous PhP3-CD3 phosphonium salt. Spontaneous deprotonation of the methyl group lead therefore to formation of the corresponding phosphorus ylide, Ph3P=CH2. This Ph3P=CH2 ylide was tested for the Wittig reaction with benzaldehyde PhCHO, generating the desired PhC=CH2 olefination product. It was noteworthy that this Wittig reaction protocol did not require an alkyl halide or a strong base for the formation of the ylide, and could be conducted in air, making it a greener procedure. The scope of the olefination reaction was extended to a number of carbonyl substrates, both aldehydes and ketones, with high conversions and selectivity. It was performed under mild conditions (34 – 80 °C), using a ratio ylide:carbonyl between 1.0 -3.0, in 2-methyl tetrahydrofuran (2-Me-THF) as solvent. The study was also extended to other alkylphosphonium methylcarbonate ionic liquids ([P8,8,8,1][OCOOCH3] and [P4,4,4,1][OCOOCH3]). It was demonstrated that, depending on the reaction conditions, it was possible to achieve not only the transfer of a =CH2 fragment, but also the selective transfer of the bulkier alkyl group e.g. =CH(CH2)nCH3, giving access to a variety of olefins. Cis-trans selectivity was in the range 20-80
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